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ba_aed104_8_e.doc
The transducer electronic unit is adjusted in the factory to the no-load and the nominal load of the transducer.
The electronic unit determines a factory characteristic through the commands
SZA
and
SFA
from these
measured values and images the measured values following later by means of this characteristic.
The following measured values are delivered according to output format (COF):
Output format
Input signal
Measured values
at
NOV = 0
Measured
values at
NOV > 0
Delivery status
NOV=0
Binary 2 characters
(Integer)
0...Nominal load
0 ... 20 000 Digit
0 ... NOV
Binary 4 characters
(Long Integer)
0...Nominal load
0 ... 5 120 000 Digit
0 ... NOV
ASCII
0...Nominal load
0 ... 1 000 000 Digit
0 ... NOV
x
You have the possibility of adapting the characteristic to your requirements (i.e. scale characteristic)
correspondingly with the parameter pair
LDW
and
LWT
and to standardize the measured values to the required
scaling value (e.g. 3000d) via the command
NOV
.
4.2 Signal
processing
Measuring
bridge
Ampli-
fier
Filter
Factory
scaling
Measur.
rate
User scaling,
Linearization
ZTR, ZSE
Net
ASF
ICR
ADC
Net
measured
value
Gross
measured
value
SZA
SFA
LDW
LWT
NOV
LIC
TAV, TAS
TAR
FMD
Fig. 4.2.1:
Signal flow diagram
After amplification and AD conversion, the signal is filtered by adjustable digital filters (command
ASF
). The
factory characteristic is determined with the aid of the commands
SZA
and
SFA
.
The measuring signal bandwidth (digital filter) is set with the command
ASF
. The measuring rate (number of
measurements per time unit) can be changed depending upon the filter bandwidth with the command
ICR
.
The user can set his own characteristic (commands
LDW, LWT, NOV
) without changing the factory calibration
(
SZA/SFA
). Furthermore, gross/net switch-over is available (command
TAS
). Using the command
ZSE
an
automatic switch-on zero setting can be activated. An automatic zero tracking function (
ZTR
) is also available.
For a linearization of the scale characteristic, the command (LIC) is available (with a polynomial of the 3rd
order). The polynomial parameters can be determined by means of a HBM PC program AED_LIC.
The current measured value is retrieved by the command
MSV?
. The format of the measured value (ASCII or
binary) is set by the command COF. An automatic measured value output can also be selected via the
command
COF
.
Two types of digital filters, which are switched over using the command
FMD
, are implemented in the AED. At
FMD0
filters lower than 1 Hz bandwidth are also available. In the filter mode
FMD1
, filters with fast transient
recovery are activated with high damping in the stop band. You will find detailed information in the chapter
‘Individual descriptions of the commands’.